Microfluidic passage with protective layer

Abstract

A microfluidic die may include a microfluidic passage and a protective layer provided adjacent to internal surfaces of the microfluidic passage. The protective layer may include a protective nano-crystalline material and a protective amorphous matrix encapsulating the protective nano-crystalline material.

What is claimed is: 
     
       1. A microfluidic die comprising:
 a microfluidic passage; 
 a protective layer provided adjacent to internal surfaces of the microfluidic passage, the protective layer comprising:
 a protective nano-crystalline material; and 
 a protective amorphous matrix encapsulating the protective nano-crystalline material. 
 
 
     
     
       2. The microfluidic die of  claim 1 , wherein the protective layer comprises a thin film having a thickness of no greater than 1 μm. 
     
     
       3. The microfluidic die of  claim 2 , where the protective layer comprises a thin film having a thickness of no greater than 500 nm. 
     
     
       4. The microfluidic die of  claim 1 , wherein the protective layer has a surface adjacent the microfluidic passage, the surface having a roughness of no greater than 10 nm. 
     
     
       5. The microfluidic die of  claim 4 , wherein the roughness of the surface adjacent the microfluidic passage is no greater than 5 nm. 
     
     
       6. The microfluidic die of  claim 1 , wherein the protective nano-crystalline material is selected from a group of materials consisting of Titanium Carbon Nitride (TiCN), Tantalum Carbon Nitride (TaCN), Niobium Carbon Nitride (NbCN), Titanium Boron Nitride (TiBN), Tantalum Boron Nitride (TaBN), Niobium Boron Nitride (NbCN), Titanium Tantalum Carbon Nitride, Titanium Tantalum Boron Nitride, titanium Niobium Carbon Nitride, Titanium Niobium Boron Nitride, Tantalum Niobium Carbon Nitride and Tantalum Niobium Boron Nitride. 
     
     
       7. The microfluidic die of  claim 6 , wherein the protective amorphous matrix is selected from a group of protective amorphous matrices consisting of silicon carbon (SiC) and silicon boron (SiB). 
     
     
       8. The microfluidic die of  claim 6  further comprising a thermal resistor along the microfluidic passage, wherein the protective layer is sandwiched between the thermal resistor and the microfluidic passage. 
     
     
       9. The microfluidic die of  claim 8  further comprising an ejection orifice extending from the microfluidic passage opposite the thermal resistor. 
     
     
       10. The microfluidic die of  claim 1 , wherein the protective layer is selectively patterned on internal surfaces of the microfluidic passage. 
     
     
       11. A method for forming a microfluidic die, the method comprising:
 providing a substrate; 
 forming a protective layer upon the substrate, the protective layer comprising:
 a protective nano-crystalline material; and 
 a protective amorphous matrix encapsulating the protective nano-crystalline material; and 
 
 forming a microfluidic passage forming layer on the substrate to form the microfluidic passage along the protective layer. 
 
     
     
       12. The method of  claim 11 , wherein the microfluidic passage forming layer is formed on the protective layer. 
     
     
       13. The method of  claim 11 , wherein the protective layer comprises a thin film having a thickness of no greater than 1 μm. 
     
     
       14. The method of  claim 13 , wherein the protective layer has a roughness adjacent the microfluidic passage of no greater than 10 nm. 
     
     
       15. A fluid ejection die comprising:
 a substrate; 
 a thermal resistor supported by the substrate; 
 a fluid passage forming layer supported by the substrate to form a microfluidic passage opposite the thermal resistor; and 
 a protective layer supported by the substrate between the microfluidic passage and the thermal resistor, the protective layer comprising:
 a protective nano-crystalline material; and 
 a protective amorphous matrix encapsulating the protective nano-crystalline material. 
 
 
     
     
       16. The microfluidic die of  claim 15 , wherein the protective layer comprises a thin film having a thickness of no greater than 1 μm. 
     
     
       17. The microfluidic die of  claim 15 , wherein the protective layer has a surface adjacent the microfluidic passage, the surface having a roughness of no greater than 10 nm. 
     
     
       18. The microfluidic die of  claim 15 , wherein the protective nano-crystalline material is selected from a group of materials consisting of Titanium Carbon Nitride (TiCN), Tantalum Carbon Nitride (TaCN), Niobium Carbon Nitride (NbCN), Titanium Boron Nitride (TiBN), Tantalum Boron Nitride (TaBN), Niobium Boron Nitride (NbCN), Titanium Tantalum Carbon Nitride, Titanium Tantalum Boron Nitride, titanium Niobium Carbon Nitride, Titanium Niobium Boron Nitride, Tantalum Niobium Carbon Nitride and Tantalum Niobium Boron Nitride. 
     
     
       19. The microfluidic die of  claim 15  further comprising an ejection orifice extending from the microfluidic passage opposite the thermal resistor. 
     
     
       20. The microfluidic die of  claim 15 , wherein the protective layer is selectively patterned on internal surfaces of the microfluidic passage.